Nuprl Lemma : copath-extend_wf
∀[A:𝕌']. ∀[B:A ⟶ Type]. ∀[w:coW(A;a.B[a])]. ∀[p:copath(a.B[a];w)]. ∀[t:coW-dom(a.B[a];copath-at(w;p))].
  (copath-extend(p;t) ∈ copath(a.B[a];w))
Proof
Definitions occuring in Statement : 
copath-extend: copath-extend(q;t)
, 
copath-at: copath-at(w;p)
, 
copath: copath(a.B[a];w)
, 
coW-dom: coW-dom(a.B[a];w)
, 
coW: coW(A;a.B[a])
, 
uall: ∀[x:A]. B[x]
, 
so_apply: x[s]
, 
member: t ∈ T
, 
function: x:A ⟶ B[x]
, 
universe: Type
Definitions unfolded in proof : 
so_apply: x[s]
, 
so_lambda: λ2x.t[x]
, 
true: True
, 
less_than': less_than'(a;b)
, 
le: A ≤ B
, 
top: Top
, 
subtype_rel: A ⊆r B
, 
subtract: n - m
, 
squash: ↓T
, 
sq_stable: SqStable(P)
, 
uimplies: b supposing a
, 
uiff: uiff(P;Q)
, 
prop: ℙ
, 
false: False
, 
implies: P 
⇒ Q
, 
rev_implies: P 
⇐ Q
, 
not: ¬A
, 
and: P ∧ Q
, 
iff: P 
⇐⇒ Q
, 
or: P ∨ Q
, 
decidable: Dec(P)
, 
all: ∀x:A. B[x]
, 
nat: ℕ
, 
copath-at: copath-at(w;p)
, 
copath: copath(a.B[a];w)
, 
copath-extend: copath-extend(q;t)
, 
member: t ∈ T
, 
uall: ∀[x:A]. B[x]
Lemmas referenced : 
coW_wf, 
copath_wf, 
copath-at_wf, 
coW-dom_wf, 
coPath_wf, 
coPath-extend_wf, 
le_wf, 
le-add-cancel, 
add-zero, 
add_functionality_wrt_le, 
add-commutes, 
add-swap, 
add-associates, 
minus-one-mul-top, 
zero-add, 
minus-one-mul, 
minus-add, 
condition-implies-le, 
sq_stable__le, 
not-le-2, 
false_wf, 
decidable__le
Rules used in proof : 
universeEquality, 
functionEquality, 
cumulativity, 
instantiate, 
equalitySymmetry, 
equalityTransitivity, 
axiomEquality, 
minusEquality, 
intEquality, 
voidEquality, 
isect_memberEquality, 
lambdaEquality, 
applyEquality, 
imageElimination, 
baseClosed, 
imageMemberEquality, 
isectElimination, 
independent_isectElimination, 
independent_functionElimination, 
voidElimination, 
lambdaFormation, 
independent_pairFormation, 
unionElimination, 
hypothesisEquality, 
dependent_functionElimination, 
extract_by_obid, 
natural_numberEquality, 
hypothesis, 
because_Cache, 
rename, 
setElimination, 
addEquality, 
dependent_set_memberEquality, 
dependent_pairEquality, 
thin, 
productElimination, 
sqequalHypSubstitution, 
sqequalRule, 
cut, 
introduction, 
isect_memberFormation, 
sqequalReflexivity, 
computationStep, 
sqequalTransitivity, 
sqequalSubstitution
Latex:
\mforall{}[A:\mBbbU{}'].  \mforall{}[B:A  {}\mrightarrow{}  Type].  \mforall{}[w:coW(A;a.B[a])].  \mforall{}[p:copath(a.B[a];w)].
\mforall{}[t:coW-dom(a.B[a];copath-at(w;p))].
    (copath-extend(p;t)  \mmember{}  copath(a.B[a];w))
Date html generated:
2018_07_25-PM-01_39_12
Last ObjectModification:
2018_07_18-PM-07_49_38
Theory : co-recursion
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